Objective Quantitative evaluation of early subclinical myocardial damage in patients with COVID-19 infection by two-dimensional speckle tracking imaging（2D-STI）. Methods A total of 59 patients with post-COVID-19 infection after the COVID-19 outbreak was lifted in China on December 7, 2022 were continuously enrolled as the observation group, and 60 outpatients before COVID-19 epidemic were selected as the control group. Basic clinical data and markers of myocardial injury and other laboratory indicators of patients were collected. Left ventricular ejection fraction, left ventricular diastolic function, left ventricular global longitudinal strain (GLS) and 18-segment strain values were evaluated by two-dimensional echocardiography and 2D-STI. Heart rate, LVEF, E/A, GLS and 18-segment strain values were calculated and compared among all groups. Results We found that most patients after COVID-19 infection showed non-myocarditis characteristics, mainly manifesting cardiovascular discomfort such as chest tightness, chest pain and palpitation. Further studies showed that left ventricular diastolic function and GLS were significantly decreased in patients after COVID-19 infection compared with those without infection, while left ventricular systolic function was not significantly different. Eighteen segment strain analysis showed that in the COVID-19 group, 10 segments, including basal anteroseptal, mid anterior, mid anteroseptal, mid inferolateral, mid anterolateral, apical anterior, apical anteroseptal, apical inferior, apical inferolateral and apical anterolateral were significantly reduced. Subgroup analysis of post-infection time showed that the GLS of patients showed a gradual improvement trend with the extension of COVID-19 recovery time. Conclusions Most patients with COVID-19 infection have non-myocarditis features, mainly showing cardiovascular discomfort such as chest tightness, chest pain and palpitations. After COVID-19, left ventricular diastolic function and GLS were decreased, and the absolute value of strain was significantly decreased mainly in the left ventricular apex. The patients' heart function and GLS gradually improved with the prolonged recovery time of COVID-19. The application of 2D-STI technique can quantitatively evaluate early subclinical myocardial damage in patients with long novel coronavirus syndrome, and probably provide data support and guidance for clinical diagnosis and treatment of novel coronavirus patients.